A wide variety of tools and processes have been developed to clean swimming pools and similar things (fountains, spas—both above and below ground, fish ponds, etc.), including and in addition to those described in my previously-issued U.S. Pat. Nos. 5,473,786 and 6,302,277. Among those devices and methods are devices that are commonly referred to as “leaf rakes”. Commonly, leaf rakes utilize a modular approach in order to permit replacement of parts of the leaf rake that tend to wear out. Among such prior art modular devices are some of mine (the Piranha Net PA-500 and Stingray Net SR-400), and others such as Purity Red Baron. Devices such as these typically include a replaceable net sized and configured to fit a frame, a replaceable elongated clip that serves as a retaining means to hold the net to the frame and a contact edge or lip (or cleaning surface) that makes contact with the interior surfaces of a pool. Also commonly and also modularly, an attachment means is provided to attach the frame to a handle or pole.
The Leslie's Pro Rake is another type of leaf rake that utilizes a modular approach. Its retaining means is not an elongated clip, but a very rigid, collar-like element with a net means permanently attached thereto. The collar and net means are snapped over the mouth portion of the frame during assembly. The Leslie's Pro Rake has an additional component that snaps over the front portion of the collar and on which a cleaning surface makes contact with an interior pool surface. In addition, some models of the Leslie's Pro Rake have a flexible tip on the contact portion of the additional snapping portion.
Prior art attempts to permit modular assembly and/or disassembly have many shortcomings. Among other things, the elongated clip must be stiff enough to retain the net on the frame while at the same time being flexible enough to permit ease of assembly and disassembly. Since securely retaining the net on the frame is more often a greater concern, the resulting rigidity of the elongated clip/retaining means tends to compromise the ease of assembly, disassembly, and/or replacement of parts.
Further compromise associated with rigidity occurs in the performance of the leaf rake as it is used on various surfaces found in swimming pools, spas, fountains, and other water features. In pools that have hard surfaces such as plaster, Pebble Tec, and rock, the portions of the elongated clip that make contact with such surfaces tend to last longer and perform better when they are rigid. However, in pools that have soft and smooth surfaces such as vinyl, fiberglass, acrylic, and tile, the benefits of having rigid contact portions of the elongated clip are limited. Fiberglass, acrylic and tile surfaces are generally very smooth and even slippery; sometimes these surfaces are made with varying textures that reduce slippage by giving grip to a swimmer's feet. When cleaning very smooth and slippery surfaces, the rigid contact portions of a conventional elongated retaining clip tend to glide over such surfaces almost too easily and, as a result, some debris may escape cleaning by either sliding between the clip and the smooth surface or sliding around the leaf net itself. Said another way, such rigid contact edges can prevent those contact edges from conforming very well to the surface being cleaned—the edges may not be sufficiently flexible. When cleaning surfaces that have slip reducing textures, this problem may be compounded; very small debris such as sand may easily slide between the textured surface and the contact points of a rigid elongated clip because the rigidity does not allow the contact points to conform to the variations of the textured surfaces.
Furthermore, the liners of vinyl pools, both in-ground and above ground, often lay directly upon firm surfaces such as concrete, wood, or dirt. It is not uncommon for tiny objects such as very small rocks, granules of sand, or other debris to be caught between the vinyl liner and the firm surface upon which it lays, resulting in small bumps in the liner. Though often very small, such bumps are usually detectable when struck by the contact points of a rigid elongated retaining clip during cleaning. As a result, the smoothness of motion that contributes to ease of cleaning is reduced or compromised as the rigid contact points of the cleaning tool grind against the liner. Furthermore, the small rocks and debris beneath the vinyl liner are potential hazards to the integrity of the vinyl liner, especially if the liner above those rocks and debris is subject to repeated abrasion. In extreme cases, the integrity of the liner of a vinyl pool may ultimately be compromised to the point where a leak forms in the areas where heavy abrasion occurs (such as from repeated cleanings from a leaf rake).
Additionally, the contact points of elongated clips have many possible configurations, with each configuration having unique features that contribute to the effectiveness of the cleaning tool. The profiles of some elongated retaining clips are designed to actually scoop under targeted debris during cleaning by providing a smooth, ramping transition surface that urges targeted debris into the net. Such configurations are described in my U.S. Pat. No. 5,473,786. Other profiles (such as that found on the Purity Red Baron device) are limited in their ability to lift targeted debris. Whatever the configuration, the rigidity of the elongated clip remains a factor that limits effectiveness in cleaning on some surfaces, especially vinyl liners, fiberglass, acrylic, and tile for the reasons mentioned above.
On the other hand, however, these clip elements typically cannot be made from a material that is too flexible or soft, because such material may be too easily damaged and/or it may not provide the degree of stiffness and structural integrity that is sometimes needed and desired during the cleaning process (for example, to scrape accumulated debris from the bottom of a pool, or to effectively clean a large smooth area of the pool surface).
Moreover, the elongated retaining clips currently used on leaf rakes typically are made from a single plastic substance which is extruded from a single die. Plastic extrusion is a well-known manufacturing process by which molten plastic is forced through a die, the die being a steel plate with an opening shaped so that the plastic forced through that opening has a given desired profile. As the molten plastic passes through the die, it takes on the general yet enlarged shape of the opening's profile. The newly formed molten plastic is then pulled for a distance of several yards, being stretched, formed and cooled until it takes its intended shape.
These single-material retaining clips used on leaf rakes have the dilemma discussed above; they must be both rigid enough to retain a net on a frame while also being flexible enough to permit assembly, disassembly, and reassembly with replacement parts, and their contacting edges must similarly strike a balance between sufficient stiffness and sufficient flexibility. Those compromises result in similar compromises in the pool leaf rake's performance.